I. '08. 



37 



II. Eostnim a regular prolongation of the carapace ; man 

 dible with a two-jointed palp; gill formula : — 



Podobranchiae, 



Arthrobranchiae, 



Pleurobrauchiae, 



VIL Vin. IX. 



ep. 



ep. 



ep. 



2 



X. 



XL 



XII. 



XIII. 



XIV. 



... 



... 









1 



1 



1 



1 





1 



1 



1 



1 



] 



Parapasiphae (p. 47), 



Genus Pasipha'e, Savigny. 



The three species of this genus known from British and 

 Irish waters fall into two groups : — 



I. Abdominal somites laterally compressed, but 

 not dorsally carinate ; telson truncate at 

 apex, . . . . . . 



P. sivado. 



II. Abdominal somites laterally compressed 

 and sharply carinate dorsally ; telson 

 forked at apex, . . . . . 



P. tarda. - '^^ 

 ( P. princeps.- pr» 



A tabular statement of the distinctions between these last 

 two species will be found on p. 42. 



h: 



C. /)/.. (4 .? 



Pasiphae sivado, (Rjsso). 



PL IV, fig. 12. 

 Pasiphaea sivado, Bell, 1853, fig., p. 312. 



The very rudimentary character of the pleurobranch at the 

 base of the last pereiopod is an interesting feature of this w^ell 

 know^n form. It consists of a short process bearing five or six 

 lamellae and is apparently developed quite late in the }X)st- 

 larval history of the species ; even in specimens measuring 

 30 mm. no trace of it could be found (cf. Caiman, 1903). In 

 the other tw^o representatives of the genus known from Irish 

 waters this podobranch is w^ell developed although smaller 

 than that at the base of the preceding limb. 



Size. — The largest specimen observed measures 79 mm. ; 

 individuals up to 4 ins. in length have, however, been re- 

 corded from Loch Fyne (Henderson). Off the Irish coast 

 ovigerous ' females are rarely found to measure less than 

 65 mm., but Alcock has recorded an egg-laden female from 

 Indian waters of only 48 mm., w^hile a specimen from the 

 Portuguese coast examined by the author was only 2 mm. 

 longer. 



