28 PROGREBS OF MICROSCOPICAL SCIENCE, 



(e) forming a somewhat loose and scanty network around the arteries 

 — external vasa vasorum ; (/) supplying the lobule^ of adipose tissue. 

 Two points in the description of these capillary systems are worthy of 

 special notice : one, that the sweat-glands are quite unconnected in 

 their blood-supply with the papilla, so that there is no second capil- 

 lary network in the skin, as in the kidney ; the other, that the special 

 capillaries of the adipose tissue can be recognized in the foetal 

 integument before any fat-cells have been formed. 



3. Three vascular layers may be distinguished in the human skin : 

 a deep one, supplying the subcutaneous fat and deepest part of the 

 cerium, a mid-layer for the sweat-glands, and a superficial papillary 

 network. The last discharges its blood into a venous plexus, which is 

 almost erectile in character. The three corresponding sets of veins 

 finally open into common collecting branches, visible to the naked 



^y^- . . . 



4. The author confirms the observations of those histologists who 

 have frequently met with papillae which are at once nervous and 

 vascular. 



A New Sponge is described by Professor A. E. Verrill as having 

 been obtained in the course of his recent dredgings on the coast of 

 New England. He says* it is a large species, of which several fine 

 specimens were obtained. This in general appearance and form some- 

 what resembles a Tethya, and in the character of the spicula it agrees 

 with Dorvillia Kent. This sponge consists of a broad, convex, often 

 nearly hemispherical, upper portion, two to four inches in diameter, 

 supported on a broad, stout, but short, peduncle, usually two or three 

 inches broad in large specimens, and somewhat less in height, the 

 peduncle usually forming about one-half of the total height, which 

 may be three or four inches. The peduncle is composed of very long, 

 slender, irregularly aggregated, mostly setiform spicula, more or less 

 appressed to the surface, but with the upper ends mostly free; together 

 with a few small dependent fascicles. The " head " or upper portion 

 of the sponge mass is firm and rather dense, composed chiefly of 

 radiating bundles of large and long slender spicula, often more than 

 half an inch long, many of which, at the external layer, divide into 

 thi*ee horizontal or recurved branches or prongs, each of which usually 

 forks near the end into two acute divergent branches, serving to 

 support the cortical layer, which is more or less irregular and uneven, 

 but firm ; some of the spicula referred to project beyond the surface, 

 and nearly the whole exterior is rudely and densely hispid, with long, 

 setiform, acute spicules, which project unequally from the surface, the 

 free ends ol many of them being half an inch or more in length. 

 Among the projecting spicula, and supported by them, are small, 

 elongated oval, or fusiform, masses of soft sarcode, which are probably 

 to be regarded as external gemmae. Scattered irregularly over the 

 upper surface, and especially around the periphery, are large, often 

 very elongated, rounded, or angular, sunken areas or pits, often half 

 an inch across, surrounded by a more or less prominent margin sup- 



* Sillimau's Journal, Mny, 1874. 



