132 METAPENEUS SIBOGAE. 



concave, posteriorly it ends in two obtuse or rounded lobes. 

 The slightly concave, lateral margins join the coxae of the 

 4th legs; immediately behind these coxae a salient lamina 

 extends, at either side, from the lateral margins, near the 

 posterior end of the plate, towards the coxae of the 5th legs; 

 between the plate and the thickened, transverse, posterior 

 margin there is a deep concavity. 



Length of male 70™™.^ of female 80™™.. 



6. Metapeneus distinctus, n. sp. 



Station 37. Sailus ketjil. Paternoster-islands. Depth 



27 M. and less. 

 Station 184. Anchorage off kampong Kelang, south 



coast of Manipa-island. Depth 86 M. 



A species of the Metap. akayebi-grouip, without stridulating 

 organ, closely related to Metap. mogiensis Rathb. 



Rostrum and carapace as in this species; rostrum 1 -\- \ 

 toothed, reaching just beyond the middle of 2"^^ joint of 

 antennular peduncle. Epigastric tooth at anterior fourth 

 of carapace. Sixth abdominal somite ^/^ of the length of 

 the carapace, without the rostrum. Ventral spines between 

 the bases of 2"^ pair well developed. Thelycum consisting 

 of the following parts : between the legs of the 5th pair 

 two parallel transverse plates, the anterior less broad but 

 longer than the posterior, its anterior margin emarginate, 

 outer angles dentiform, lateral margins arcuate; the pos- 

 terior plate is cut into three lobes, the outer lobes bluntly 

 dentiform, more prominent than the median one that has 

 a mucronate tip. Between the 4:^^ pair is a sunken plate, 

 a little less broad than long, with mucronate tip in the 

 middle of its anterior border. Midway between this anterior 

 border and that of the anterior of the two plates 

 between the 5th pair of legs are two small teeth that 

 have another form as in Metap. mogiensis, and between 

 these teeth and the anterior of the two plates one 

 observes a pair of acute dentiform tubercles, 



Notes from tbe Leyden jMuseum, "Vol. XXIX. 



