426 Miscellaneous. 



Finally the author describes two new species of Pterocles, namely : — 

 P. Severzowi (^ = Tctrao ccmdacutas, Grae\., = T. (dcJiata, Gmel.,= 

 T. chat((, Vail., = Pterocles caspiiis, Menetr.) from the Aralo-Caspian 

 steppes, Turkestan, Transcaucasia, and North Persia ; and P. Ellioti 

 from Abyssinia. — Bull. Acad. Imp. 8ci. St. Petersb. tome xxvii. 

 pp. 164-168. 



Investigation of certain Points in the Anatomy of Sternaspis scutata. 

 By M. Max. Eiexsch*. 



The Sternaspis measures about 0*030 metre in length and 

 0-010 metre in breadth. Its body, which is attenuated anteriorly 

 in a state of repose, is inflated in front and behind and constricted 

 in the middle when the animal, in order to move, throws forward 

 the retractile anterior portion of its body. The latter bears three 

 rows of setae, which are interrupted upon the dorsal and ventral 

 lines, and which may be conceiiled by the invagination of the ante- 

 rior region of the trunk. The mouth, which is somewhat ventral, 

 is surmounted in front by a small prominence homologous with the 

 cephalic lobe, and indicating the place occupied by the cerebroid 

 ganglia. In the posterior region we observe a ventral shield fringed 

 with tufts of setae, except at its anterior margin ; above its posterior 

 margin is placed the somewhat dorsal anus, which is surmounted by 

 two oval perforated plates garnished with numerous branchial fila- 

 ments. Towards the anterior third, upon the ventral surface, we 

 may distinguish two small conical appendages, axially perforated ; 

 these are the external terminations of the generative organs. There 

 are also small bundles of seta3 in the median ventral region of the 

 body ; but they do not appear beyond this. 



The integuments consist of a thick and resistant fibrous layer, 

 striated parallel to the surface, covered externally by a layer of 

 hairs, which alone seem to represent the epidermis, and lined inter- 

 nally with a granular stratum, in which we may sometimes succeed 

 in detecting nuclei : from this layer, which internally is in contact 

 with the muscles, a number of more or less undulated filaments 

 start, traversing the fibrous zone perpendicularly and terminating 

 in the hairs ; chloride of gold, employed as suggested by M. Kanvier, 

 gives them an intense violet colour, as also to the granular layer, 

 while the fibrous zone remains nearly colourless. I think we may 

 regard these filaments as nervous terminations. 



Further in we meet with an external layer of transverse mus- 

 cular fibres, then an inner layer of longitudinal fibres, which are 

 inserted upon the reentering lines bounding the segments. I shaU 

 confine myself here to indicating further the powerful development 

 of the retractor muscles, formed principally of two bundles placed 

 on the sides of the nervous cord, and the fibres of which ai'e im- 

 planted in front at the base of the anterior seta?, and behind upon 

 the ventral surface of the integuments : these fibres are of unequal 



* The author's examinations of this worm were made on specimens 

 from ofi" Cape Breton, in the Bay of Biscay, and from the Gulf of Lyons. 



