The branchial cavity was opened after ascending or removing the branchiostegite (gill cover) of the branchial chamber, and then the gross morphological features of the gills and associated accessory respiratory organs were examined in situ by the naked eyes, next dissected, and the findings obtained were imaged by means of a Digital Camera (Sony Inc., Japan).
These two branchial chambers were bounded ventrally by bases of the walking legs, dorsally by the median groove on back of crayfish and laterally by the gill covering (branchiostegite), while medially by thoracic body wall.
In the earlier developmental stages, a discernible, thin epithelial sheet, likely corresponding to the inner epithelium of the branchiostegite
, had a large MRC population (arrow in Fig.
4A, B) without epigastric ridge; antennal lobe obsolete; pterygostomial angle only slightly produced, rounded or slightly angular; postantennal groove shallow; branchiostegite
not inflated; surface devoid of tufts of setae.
Molt stages were based on the criteria of Drach and Tchernigovtzeff (1967) and Norman and Jones (1992): 1) soft, no calcification of the new exoskeleton; 2) early papershell, thin, flexible exoskeleton, easily depressed when touched; 3) late papershell, hard exoskeleton except for the branchiostegite
region which is compressible; 4) intermolt, completely hard exoskeleton; and 5) premolt, teeth on chelae well worn and having a less rounded appearance compared with those in earlier stages, complete exocuticle developed beneath the exoskeleton.
Recent preliminary unpublished evidence from the author's laboratory suggests that the sense organs in which this activity originates represent a small ([less than or equal to] 12) population of cuticular setae resembling in their morphology the branchiostegite
pit receptor hairs previously studied (Mellon, 1963).
Bopyrids live on shrimp, brachyurans, and anomurans and cause a conspicuous bulge of the branchiostegite
(Dall et al.
For the analyses of the respiratory movements, the right branchiostegite
of four individuals was dissected to get a clear view of the structures involved.
Ultrastructural observations of the muscle insertion and modified branchiostegite
epidermis in the larval brown shrimp, Penaeus aztecus.
Cephalothorax with small tubercles only in anteroventral regions of branchiostegites
. Small eyes.
Other symptoms of the disease include a reddish discolouration of body and appendages because of the expansion of chromatophores (53), (54), less intake of feed (55), (56), reduced preening and low response to stimulus (19), (57), loose cuticle (58), swelling of branchiostegites
because of accumulation of fluid (25), (59) and thinning and delayed clotting of haemolymph (60).
Based on this reproductive behavior, we suggest that as occurs in other freshwater decapods, such as Procambarus clarkii, where chelae were more heavily mineralized than branchiostegites
, and Astacus astacus where statistical differences were detected between sexual active and inactive animals regarding the concentration of mineral matter in both chelae and branchiostegites
(Huner & Lindqvist, 1985), mature males of C.