GENUS — LEPAS. 71 



variation in their proportional lengths, and in number, in 

 the same species. These organs have generally been con- 

 sidered to serve as branchiae ; I see no reason to believe 

 that they are more especially designed for this end, than 

 is the general surface of the body. 



Mouth. — The labium is moderately bullate, the longi- 

 tudinal diameter of this part equalling about one third, 

 or half of that of the rest of the mouth. The palpi are 

 moderately developed. The mandibles (PL X, fig. 5) 

 have five teeth with the inferior point either broad, or 

 very narrow and tooth-like. The maxillae are step-formed 

 (PI. X, fig. 9) ; the first step is sometimes indistinct and 

 curved ; and in Z.pectinafa, all the steps vary much, and 

 are more or less blended together. The outer maxillae 

 (like those at PI. X, fig. 16), are internally clothed con- 

 tinuously with spines. The olfactory orifices are not at all 

 prominent. 



Cirri. — The first pair is placed near the second pair, 

 and is of considerable length ; the second has the anterior 

 ramus thicker than the posterior ramus, and the seg- 

 ments brush-like; the segments (PL X, fig. 26) of the 

 four posterior cirri bear from four to six pair of long 

 spines, with a row of small intermediate spines : in the 

 posterior cirri of L. australis the lateral rim spines are 

 much developed ; and in those of L. fascicularis, the 

 usual pairs of large spines are lost in a broad triangular 

 brush, formed by the increase of the lateral marginal, and 

 intermediate spines. 



Caudal Apjoendages (PL X,' fig. 18/5), very small, either 

 blunt or pointed, and quite destitute of spines. 



The prosoma is well developed. The stomach is sur- 

 rounded in the upper part by a circle of large branching 

 caeca. The generative system is highly developed ; the 

 testes coating the whole of the stomach, entering the fila- 

 mentary appendages and the pedicels of the cirri ; the two 

 ovigerous lamellae contain a vast number of ova ; they are 

 united to rather large fraena, of which the sinuous margin 

 supports either a continuous row or separate tufts of glands. 



