xu 



TAP.K SKOCSHKHO 



Xiimher of species. 



Function of the 

 maxilln. 



nislribution. 



Type sprcies. 



1 havf obtaiiit'd conlirmatiim of tliis idctit iticat ion liv a ic-rxaminat ion ol ( he t vpc .specimen 

 i>f this specios of BHADY's (it is kept in the / o o 1 o j; i e a I i\l n s e ii m al (Op e ri h a fx e n). 

 Unfortunatoly only tlu' slieli is li'lt of this ini|)()rtant sppcinien; all llie oiliei' organs aic missing'. 

 As is shown by tlie lU'seription of the sub-genus given by me above, several mistakes were fimnd 

 in BHADY's description and figures. Contrary to wliat one would be iiu lined to expect from 

 BltAl>\'s statements, the type specimen exhibits a marked relationship to the species (h'seribed 

 by nie below. 



In addition to .1/. (('.) javus there are certainly two oilier species belonging to this sul)- 

 genus. namely Cypridina Bairdi G. S. BliAUV (18(55, j). 387; pi. 62, fig. 7 and 1807. p. 88; ]>!. IC, 

 figs. -Ji' ami 23) and Cifpridina asymmetrica G. W. Mi'LUOi; (Ifxxi b. p. N; pi. (i, figs. 1—12). 

 Of these two species, which are certainly very closely related to each other, tiie former is very 

 little known; the latter, on the other hand, is one of the better known representatives of this 

 sub-family. Both of them confirm the correctness of the new description of the sub-genus 

 I have given above. 



On account of the incompleteness of the descriptions it is impossible to decide whether 

 any more of the species hitherto described are to be included in this group. 



With regard to the function of the maxilla in this sub-genus it may be pointed out here 

 that the palp of this limb is certainly to be considered as an important organ of locomotion, wliile 

 the endites — as is usual in this sub-family — are masticatory organs. This double functicm 

 is rendered possible by the fact that the palp and the part from which the endites issue are 

 capable of free motion independently of eacli otliei-. 



All the forms of this sub-genus so far known come from the western j^art of tlie V a c i f i c. 

 (The locality of the type specimen is, however, unknown.) 



Type species: M. (C.) javun, G. S. BliADY, 1902 a. 



M. (Cypridinodes) acuminata n. sp. 



De'^eription: — Male: — 



Shell: — Length, 5,5 mm. Length : height, about 1,5 : 1; this applies to the left 

 valve, the right one is somewhat lower. Length : breadth, about 2:1. Seen f r o m t h e 

 side (fig. 1), it has its greatest height at about the middle and the posterior part of the shell 

 is not, at least not perceptibly, larger than the anterior part. The dorsal and the ventral margins 

 are arched rather boldly and almost uniformly and evenly, the ventral margin is, however, 

 somewhat irregular, as it is somewhat pouting anteriorly; both join the anterior and tlie posterior 

 margins without corners. The posterior part of the shell forms, at about half the height of the 

 shell, a rectangular, pointed corner. The rostrum has anteriorly a strongly projecting but 

 broadly rounded corner; its ventral corner is narrowly rounded and strongly marked because 

 the ventral part of the anterior margin of the rostrum curves inwards rather decidedly. The 

 narrow and rather deep rostral incisur is characterized by having its posterior margin defined 

 from the ventral margin of the shell by a rather strongly marked corn(>r. Seen f r o m a b o v e 



