20 Eev. T. R. R. Stebbing on Crustacea. 



examining fiutliev I found it impossible to retain that view. 

 Tlie differences are, in fact, rather numerous. The valves 

 occupy a larger proportion of the capitulum and are much 

 less opaque. In consequence of the latter characteristic they 

 allow the " primordial valves " at the umbones of the terga 

 and scuta to be seen much more clearly than they are in the 

 other species. Moreover, the membrane is devoid of the 

 foraminate appearance which it has in Dichelaspis Hoehi, and 

 the peduncle is relatively shorter. 



Terga. — These, instead of widening downwards, are con- 

 tracted below\ 



Carina. — The distal margin of the base is distinctly though 

 not deeply emarginate. 



Cirri. — These are all more elongate than in Dichelaspis 

 HoeTci^ although taken from a smaller specimen. The rami 

 of the first pair have from seven to eight joints, those of the 

 other pairs from twelve to fourteen, the joints themselves 

 being more slender, more elongate, and with more numerous 

 spines than in the preceding species. 



The caudal appendages are also longer and more slender, 

 with longer spines at the apex, and none on the margin 

 below it. The penis is not peculiarly widened. 



Size. — The specimen represented in fig. E is less than three 

 twentieths of an inch, and the capitulum is not quite two 

 twentieths. 



Both in this and in the specimens of Dichelaspis Hoehi 

 (figs. B, C, D) there were large nun)bers of narrowly oval 

 eggs. The young specimen of Dichelaspis antigum (tig. G) 

 has a capitulum measuring one twentieth of an inch in length. 

 In this specimen the sieve-like appearance of the primordial 

 valves is clearly seen. Fig. G [sc.) shows one of the scuta of 

 this specimen, from which it can be seen that up to rather a 

 late stage the two segments remain solidly united. 



Mr. Forrest informs me that he took the Cirripedes above 

 described from the maxillipeds of three different Palinurids, 

 one of which weighed twelve pounds, and had a carapace 

 10^ inches long, a pleon of 11 inches, and antennas con- 

 siderably truncated, but still measuring 24 inches in length. 

 Whether the two species of Dichelaspis came from different 

 species, or even difterent specimens, of Palinuridfe, I am not 

 in a position to decide. The Trichelasjns Forresti, described 

 in this Magazine in May last as taken on a crayfish, is a 

 guest of Panulirus argus (Latreille), which, according to the 

 modern use of the terms, may be more properly called a 

 crawfish. 



