56 W. Lilljeborg on the Genera Liriope and Peltogaster. 



pallium seems to belong to a particular grade of development 

 both in P. Paguri and P. sulcatus. 



Peltogaster sulcatus, Lilljeborg. 



In the arrangement of the parts of the body, this species agrees 

 with the preceding. The outer chitinous membrane of the pal- 

 lium is destitute of longitudinal bands or raised lines ; and the 

 muscular membrane has the cellular layer thinner and the fibrous 

 layer more developed, forming a compact stratum of distinctly 

 striated fibres. The outer membrane of the ovarian sac is also 

 destitute of longitudinal bands, and its muscular membrane is 

 much thinner than in P. Paguri. The testes are of a different 

 foi-m (see Annals, vol. vi. pi. 4. fig. 11). They are small in 

 specimens with a large sac of ova, and largest in small specimens 

 without an oviferous sac. Sometimes they are found empty, 

 sometimes filled with granules and cells with distinct nuclei, and 

 enveloping a smaller sac or having double walls (PI. II. fig. 10). 

 On issuing from the testis, the canal, in the specimen figured, 

 was a little thickened and opake. The extremity which was 

 attached to the membrane (c, of the future oviferous sac ?) was 

 slightly enlarged, having its margins uneven and rather thick. 

 At this point the canal appeared to have traversed the mem- 

 brane, on the other side of which there was a vesicle containing 

 a smaller one [b) fixed to the orifice of the canal. The spermo- 

 genous cells in these testes were less developed than in that of 

 Apeltes, in which their nature was clearly seen. 



The ovaries are nearly of the same form as in P. Paguri. In 

 neither species could the author find in the ovarian sac any 

 organ corresponding with the supposed cement-gland of Saccu- 

 lina, which seems to support the opinion that this may be the 

 testis. No orifice for the escape of the ova could be detected. 



The form of the adult animal differs a little from that repre- 

 sented in the author's previous memoir; it is shown from a 

 living specimen in PI. III. fig. 1. Fig. 2 represents a specimen, 

 preserved in spirit, fi'om which the young had escaped, and in 

 which the ovaries contained no eggs. A great part of it is 

 empty ; the small ovarian sac [e) extends along the lower part 

 of the body from end to end. It is pretty closely surrounded 

 by the muscular membrane [d] of the pallium, which is con- 

 tracted and widely separated from the outer chitinous membrane. 

 At the anterior extremity [a], the anterior part of the ovarian sac 

 is forced through the pallial orifice ; it has burst, and let out a 

 portion of its contents. Sometimes similar empty specimens 

 are met with alive, but they are probably near the end of their 

 existence. 



