Rev. A. M. Norman on Recent Eryontidse. 175 



c. Polycheles typhlops, Heller. A male from the - Porcu- 



pine ' expedition, which I had examined, is charac- 

 terized by the last pereiopods being simple. 



B. Females; last pereiopods chelate. 



d. Polyckeles typhlops, Heller. A specimen dredged by 



the ' Porcupine ' expedition. 



e. Willemoesia leptodactyla, Suhm. A female, having the 



last pereiopods chelate. This specimen is said by 

 Suhm to be a male ; but it is clear that he fell into an 

 error as regards the sex ; for he says " at the coxal 

 joint of the third pereiopod are the genital openings," 

 which statement, together with his figure (pi. xiii. 

 fig. 2) of the first pleopod, clearly prove that the type 

 specimen was a female. 



It will thus be seen that before the publication of Mr. Bate's 

 paper all known specimens which had simple last pereiopods 

 were males, while such as had those limbs terminated by chela3 

 were females. 



2. That the male (c) and the female (d) represent the two 

 sexes of one and the same species, and that therefore the ache- 

 late or chelate character of the last pereiopods is a modification 

 dependent upon sex. 



I stated in my former note that I considered the two speci- 

 mens taken by the ' Porcupine ' expedition (see Proc. Roy. 

 Soc. 1870, p. 154) to be male and female of Polycheles typh- 

 lops, adding, " my conclusion that their difference is sexual 

 may be wrong." Mr. Bate has commented on these words as 

 though I did not know the sex of the individuals examined ; 

 but to any one who reads the whole passage it will be at once 

 obvious that my argument was that those structural differ- 

 ences which he regarded as generic I found to accompany 

 difference of sex, and regarded as sexual. The following- 

 detailed description of this male and female will enable other 

 carcinologists in some degree to form their own opinions. 



Polycheles typhlops, Heller*. 



1862. Polycheles typhlops, Heller, Beitrage zur nahern Kenntniss der 

 Macrouren, Sitzungsberichte der Akad. der Wissensch. nuith.-nat. 

 CI. Bd. xl. Abth. 1, p. 389, pi. i. figs. 1-6. 



1863. Polycheles typhlops, Heller, Crustaceen des siidlichen Europa's, 

 p. 211, pi. vii. figs. 1, 2. 



* If Heller's figures are absolutely correct, tbe form bere described is a 

 different species ; but with present knowledge I do not feel justified in 

 giving it a different name to that under which I recorded it in the ' Por- 

 cupine ' Report (Proc. Roy. Roc. 1870, no. 125, p. 154). 



13* 



