•3S TAOR SKOC.SHHUC. 



Sub-Genus Siphonostra n. sub-gen. 



I^csrription: — Slii-ll: Tliis is clonfiatod :iii(l lias a wcll-dcvclnpi'd, licak-sliapcd 



posterior process. Tlio rostral incisvir is docp and nairow. Near tlic iinici cdLjc nl the iiicisur tliiTc 

 aro two inodial bristles situated close to eacli otlicr. I'listeriorly, wilhiii the posterior margin ol 

 tlie shell, the list is not developed. Seen from inside, the posterior licak-like process appears 

 to have thin walls and to be constructed in ^nc\\ a way that when (lie two valves are close to 

 each other a rather wide tube, a siphon, is formed, a character wliicli lmvcs the siib-gemis its 

 name. With rather strong calcification. Ttie forms are of moderate size. 



First antenna: — This is comparatively short and moderately slender; with eiglil 

 joints; the proportions between the joints dill'er rather slightly from those given in the diagnosis 

 of the sub-family; cf. the description of the species. The sensory bristle of the fifth joint has 

 a comparatively small nundier of sensory filaments (always fewer than thirteen?). 



Second a n t e n n a: — Tlie p r o t o |) o d i t e lias a medial-distal bristle. K x o- 

 p o d i t e: The liri.stle of the second joint is rather strongly developed. Some of the natatory 

 bristles of the following joints have, in addition to natatorv hairs, powerful spines as well. 

 The third to the ninth joints have basal spines. The e u d o p o d i t e is reduced. (Similar 

 in the males as in the females? Cf. below that Cypridina hirxuta CJ. W. Ml'l.i.i i! may possibly 

 belong to this sub-genus.) The bristle ol' the end joint is long. 



31 a n d i li 1 e: — Protopodite: The enditc on the co.valf is rather weaklv bifur- 

 cated di.stally, furni.shed with a rather powerful equipment of spmes especialU- mediallv-distallv; 

 the spines only with rather a slight tendency towards arrangement in groups. This joint has 

 no bri.stle except the small one on the endite. Basale: Of the ventral bristles one d-bristle is 

 verv long, with numerous long secondary bristles at the middle arranged in irregidar 

 groups and with short hairs distally; the other ventral liristles on this joint are more 

 or less short and have short hairs or are l)are. This joint has three bristles dorsally. 

 E n d o p o d i t e: The first joint has four bristles ventrally. The end joint has seven 

 bristles, of which the two middle ones are powerful and claw-shaped and of about the 

 same length and strength. 



.Maxilla: — Protopodite: The coxale has distally a single bristle with sliort, 

 fine hairs or almost bare. Proximally on tlie f)utside of the third endite there is a single bristle. 

 On the boundary between the basale and the fir.st endopodite joint there are three bristles, 

 one close to the exopodite, one at about the middle of the inside of the palp and one on the 

 anterior edge of the latter. Dorso-distally on the coxale there is a rather large and .somewhat 

 lamelliform epipodial appendage. The exopodite is comparatively well 

 developed and has close, fine, long hairs; it is not displaced distally. The endopodite is 

 very wide and of moderate length. 



Sixth limb: — The second exopodite joint is very short, broader than it is long, 

 furnished with rather few bristles; the posterior ones of these bristles are not stiikingly larger 

 tlian the others. 



