1 882.] Some of its Developmental Stages. J 



members of this family, is somewhat distorted and unsymmetri- 

 cal, one side having narrower segments than the other, and is 

 therefore of a triangular shape. 



Degeneration as a result of parasitism is manifested in the 

 absence of eyes as well as antennae proper, in the clumsy form of 

 the feet and the much reduced mouth-parts. The head evidently 

 consists of two unequal fleshy lobes. The dorsal cephalic lobe 

 is triangular and somewhat unsymmetrically placed, the ventral 

 lobe is of subquadrate shape, anterior angles produced, posterior 

 angles rounded, with the middle of its posterior part prolonged 



Of the mouth parts I was unable to find more than one pair of 

 maxillae inserted at the sides of the ventral cephalic lobe. They 

 constitute a flat, roundish, terminal piece, the palpus, with nine 

 marginal hyaline tentacles j 1 the basal joint is connate with and 

 obliquely inserted into the median lobe. A number of muscle- 

 nerves (muscle and nerve together) run to the tip of the basal 

 maxillary joint, some of which enter the palpus, others (three) 

 distribute themselves along the outer tip of the former, entering 

 three longer and stouter marginal tentacles. A beautiful den- 

 dritic arrangement of black pigment is found near the base of the 

 palpus. 



From underneath the body of the ventral cephalic lobe arise 

 a number of narrow, ligulate, gill-like appendages, which are, in 

 the live animal, kept in constant rapid paddling motion. 2 Viewed 

 under higher microscopic power, they exhibit a granular struc- 

 ture with longitudinal, hyaline, evidently lacunary canals. If it 

 was not for their abnormal position near the anterior part of the 

 body and their structure, I should regard them as gills, but to be 

 consistent, am obliged to see in them paddling organs for the 

 purpose of aerating the eggs or embryos contained in the mar- 



The seven pair of feet are curved forward and downward, and 

 terminate in an indistinct hook-like knob. The black pigment is 

 very irregularly distributed in the feet, some are all yellowish, 

 others but slightly pigmented, and again others are nearly all 

 black. This I have observed in live specimens, and it seemed to 



1 Compare with C. Spence Bate and J. O. Westwood's History of the British ses- 

 sile-eyed Crustacea, Vol. u, p. 218, fig. 9. 

 J C. SpenceB.Ueand J. O. Westwood, op. citat. p. 220. * * * furnished with 



