CRYPTOTHIRIA. 259 
Sacculina purpurea, which it kills, but whose roots, not- 
withstanding, continue to grow and frequently attain 
an extraordinary development. 
“In the genuine Bopyride all the feet are of the same 
form, while in Entoniscus and Cryptoniscus the sixth (or 
last) pair show a very different structure.” The larva 
of Cryptoniscus has the sixth pair of pereiopoda long, 
slender, and styliform. That of Entoniscus has the 
same limbs long and slender, with large and powerful 
prehensile claws. | 
M. Hesse, in his Fourth Memoir on Rare or New 
Crustacea of the coasts of France, ‘‘ Ann. des Sci. Nat. 
1864, ser. v. vol. ii. p. 281,” described and figured the 
female of Peltogaster tau, which he found on Paguri, 
together with its monoculoid-cirriped-like embryo. More 
recently (in his Tenth Memoir, Jdzd. vol. vi. p. 321, 1866) 
he gives an elaborate account of P. paguri, in which he 
describes an animal, of which he had only taken a single 
specimen on a Pagurus, and which he considers, without 
sufficient proof, as the male, together with the female, 
and the young animal in its earliest stage of develop- 
ment. The earliest form of the larva he describes as 
resembling that of the Entomostracous crustacea, and 
states that, as in all of the suctorial crustaceans, the 
larva has three pairs of appendages. He also describes 
it as having lateral processes on each side of the anterior 
margin of the head, and that these processes are im- 
mature antenne, thus proving its relationship with the 
Cirripedes, and leading us to infer that the parent animal 
which he figures as the female is bisexual, and that his 
supposed male has no connection with the female, but 
must be considered as that of a Bopyroid crustacean, 
possibly of a Cryptothiria in an advanced stage of 
Sa 
