THE GENUS ANASPIDES. 793 



thoracic limb. It is accordingly conceivable that we have in Anaspides, more nearly 

 than in any other Malacostracan, the primitive gills in primitive number and position. 

 The same very learned carcinologist maintains * that the brood-plates of the Edrioph- 

 thalmata, and of the Mysidze, as well as the branchial plates of the Amphipoda, spring, 

 in their first development, not from the inner but from the outer side of the limb, and 

 are in fact epipodites. And we venture to suggest the possibility, or even likelihood, 

 of the double epipodites of Anaspides representing the gills and brood-plates of the 

 Amphipoda, to which, in their ovate flattened form, they are not destitute of a certain 

 resemblance. t 



The presence of two movably articulated lobes springing from the inner face of the 

 coxa in the maxillipeds is a feature which, so far as we know, is without a parallel 

 among the Malacostraca. A single simple lobe is developed in the same position in the 

 Euphausiidse, but not in the Mysidse. In the latter, the joint corresponding to the 

 coxa is small or rudimentary, but an internal lobe or lacinia springs in their case from 

 the enlarged second joint. Somewhat similar processes are developed from the second 

 and third joints of the maxillipeds in the Edriophthalmata. It seems not improbable 

 that the presence of two pairs of lateral appendages, internal lobes and epipodial 

 lamellae, springing from the coxal joint of the maxilliped, may indicate that this joint 

 represents the fusion of two joints. Hansen | has given reasons for believing that the 

 protopodite of the Crustacean limb is primarily three-jointed, not two-jointed as hitherto 

 believed. The pre-coxal joint which he finds in Nebalia, and which, in the higher 

 forms, is fused with the body, may possibly, in Anaspides, be fused with the coxal joint, 

 and carry the proximal inner lobe of the maxilliped as well as the proximal epipodial 

 lamella of that and the succeeding limbs. 



Among minor features of interest in the thoracic legs of Anaspides, we note the 

 reduction in size of the second joint, and its fusion with the third in the posterior 

 members of the series. This joint is in the Euphausiidse of much greater size, and 

 in the Mysidse attains, in the maxillipeds, an exaggerated development. Its fusion with 

 the third joint has no parallel among the Schizopoda, but the same feature is found in 

 the thoracic legs of many Decapods, especially in Boas' group of Reptantia. 



Another noteworthy point is the presence on the terminal joint of all the legs of a 

 number (4-5) of stout curved claws. In the Euphausiidse the terminal joint of the 

 thoracic legs is tipped by a brush of setse, while in most other Malacostraca the leg 

 terminates in a single stout claw. Anaspides preserves for us a transitional stage 

 between these two conditions, and it is interesting to note that, in the posterior thoracic 

 legs, one of the claws exceeds the others very much in size, forming a further step in 

 the direction of the " monodactyle " condition. With regard to the presence of eight 

 joints in the thoracic legs, Anaspides may be compared with the Mysidan Siriella, 



* Of. cit., p. 34. 



t The resemblance of the gill plates of Anaspides to those of Amphipoda is mentioned by Mr Thomson in hia 

 preliminary paper, I.e. 



\ Zool. Am., xvi., 1893, p. 193. 



