LANUGINELLA PUPA. 9 



manner, formin«;' n eontinnons basal plate in wliieli the iiidividnal 

 spicules ean without diiticulty be recognized in their proper 

 forms. 



The Jiypoderiiial'ta closely resemble the parenchymal oxv- 

 liexactins in character, except in being always devoid of a distal 

 ray. The cruciate paratangentials, 1 mm. or over in axial length 

 and up to 34 !'■ in thickness near the center, are usually in a 

 slightl}" convex plane in conformity with the curvature of the body- 

 surface. They may exhibit a sparing quantity of obsolete micro- 

 tubercles near the pointed end (PL L, lig. ('») or may be quite 

 smooth throughout. The unpaired proximal ray, more generally 

 smooth all over, is straight and ma}' be nearly three times as 

 long as the paratangential. 



As before mentioned, the hypodermalia in certain specimens 

 are protruded through the dermal layer, their paratangentials thus 

 forming a veil over the external surface. In one such veiled 

 specimen, — namely, the one depicted in PL I., fig. 1, — I have 

 found most of the prostalia to be rough-surfaced on the paratan- 

 gentials (PL I., fig. 7) as well as on the shaft, but the latter 

 only for a short distance from the spicular center. This shagreen- 

 like roughness, which is known to exist also on the same spicules 

 of several other Rossellids, is due to minute, fine, erect and 

 closely set processes. On the paratangentials, the processes are 

 most pronouncedly developed on the outer surface ; laterally they 

 become obsolete, leaving the inner surface along the middle line 

 nearly smooth. Xot that all the prostal pentactins are shagreened 

 in the manner described, for some are quite devoid of this 

 characteristic. On the other hand, among the hypodermalia, /. 

 c, the prostalia before protrusion, there occasionally occur such 



