ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 



641 



New Parasitic Copepod.* — Prof. J. Leidy describes a new species 

 of Chalimus {C. tenuis) found attached to the tail-fin of a LeptocepJialus ; 

 it is considerably less than half the size of G. scomheri described and 

 figured by Dr. Baird in his work on British Eutomostraca. 



Remarkable Crustacean Parasite, t — Dr. G. H. Fowler gives an 

 account of a remarkable crustacean parasite allied to Laura and Syna- 

 goga, and makes some remarks on its bearing on the phylogeny of the 

 Entomostraca. The name proposed for the new genus is Petrarca hathy- 

 adidis, as it was found, represented by these individuals, in the mesen- 

 terial chambers of Bathyactis symmetrica. 



The animal is nearly spherical externally and measures 1 ' 5 to 1*8 

 mm. in diameter. The general relations of the body, limbs, and 

 carapace are those of a Lejpas without a peduncle, with the terminal 

 penis bent forwards under the thorax, the limbs much reduced, the 

 mantle not carrying calcareous plates but greatly swollen by the growth 

 of the internal organs into its substance. The antenna are terminated 

 by two strong dorsally directed hooks ; the oral cone contains a pair of 

 weak crushing mandibles, and behind it there are six pairs of thoracic 

 appendages, of which the last five are simple leaf- like flabella; they are 

 all devoid of hairs or spines. The body is prolonged into a trumpet- 

 shaped penis slightly bifid at the free end. The epidermis is a single 

 layer of flattened cells and is covered by a thin chitinous cuticle ; there 

 is no evidence of any calcareous deposit. The lining membrane of the 



Copepoda Phyllopoda Ostracoda Ascothoracida Cirripedia 



Cypridiform larva 



Protostraca 



* Proc. Acad. Nat. Sci. Philad., 1889, p. 95. 



t Quart. Journ. Micr. Sci., xxx. (1889) pp. 107-21 (1 pi.). 



