368 Transactions. — Zoology. 



distinctively produced in the forms previously referred to — is 

 not found in this genus, nor, indeed, is there any appearance 

 of a mouth-opening. The antennae, foot-jaws, and three pairs 

 of legs are all represented by sac-like appendages ; the fourth 

 pair of legs is quite absent. 



Fam. LEEN.EODEA. 

 Genus, Penella, Oken. 



In the females of this genus the body is slender, cylindri- 

 cal, and much elongated. The head is rounded and some- 

 what irregular in form, and behind it arise two arm-like lobes. 

 The thorax or neck-part exhibits no segmentation, and is only 

 indistinctly separated from the genital segment. This latter 

 part is gi'eatly elongated, and constitutes the largest part of 

 the body. At its posterior extremity spring the narrow, 

 straight oviferous tubes. The abdomen protrudes as a long, 

 somewhat flattened portion, bearing on both sides a large 

 number of styliform, thread-like appendages. The antennae 

 and foot-jaws are difficult to distinguish in the head part, as 

 the}' are more or less hidden by a mass of short slender tube- 

 like processes. Behind the head all four pairs of feet are 

 placed in close succession, and all in a very rudimentary con- 

 dition. 



The male is ver}' small, almost spherical in form, and 

 carries on the anterior portion a conical sucker furnished with 

 several styliform appendages, and on the inferior face two 

 pairs of very large sub-cheliform limbs, by means of which he 

 holds on to the female. 



1. Penella histhphorl, n. sp. Plate XXVIII., fig. 2. 



In the absence of the full literature of this remarkable 

 genus I advance this species provisionally, as it is very dis- 

 tinct in form from any figured or described in Bronn or 

 Milne-Edwards. 



The head is in the form of a rounded cup about 5mm. in 

 diameter, and anteriorly presents a mass of botryoidal or 

 grape-like processes, which are slightly arranged in about 

 four parallel masses. Apparently the mouth-organs are 

 placed among these. The arm-like processes behind the head 

 extend horizontally to a length of lonnn. on each side. Be- 

 tween them and projecting a little posteriorly is a rounded 

 protuberance. The four pairs of thoracic feet are very minute, 

 and each consists of a small sub-acute lobe (somewhat similar 

 to those in P. sagitta). The genital segment is separated 

 by an imperfect constriction from the thorax, and is about 

 65mm. long, increasing in width posteriorly. It shows faint 

 transverse marks throughout its length. The abdomen is 



