180 PEECT SLADEN TEUST EXPEDITION. 



The following measurements were taken of the spindles : — -408 X '102, -306 X '108, 

 "187 X "051 mm. There are also a few tri- and quadri-radiates and irregular forms : — 

 •340 X -119, -214 X -102, -204 X -085 mm. 



In the canal-walls spicules are very numerous ; it is the extreme thinness of the 

 canal-walls themselves that gives the stem its fiaccidity. There are a few cluhs and 

 slender spindles and ii'regular forms, hut the predominant spicules here are large stout 

 spindles (1-190X"25, '850 X "30, '765 X "136 mm.), closely covered with very numerous 

 small warts, which may be arranged in zones. 



The colour of the whole colony is a brownish cream ; the spicules are colourless. 



Locality. S.W. Indian Ocean, precise record lost. 



Genus SCLERELLA 



> &• 



Uigid Nephthyid colonies with numerous digitiform lobes thickly covered with sessile 

 polyp-calyces, which are curved over so that the mouth is hidden. The tentacles are 

 simply inturned, leaving an 8-lobed aperture. Very characteristic are the massive 

 spicules of irregular " otoUth "-like form which lie on the walls of the numerous 

 longitudinal canals ; they occur from the base, where many protrude on the surface, 

 to near the tips of the finger-like lobes, and they give the interior of the colony a 

 Siphonogorgid-like texture. The calyces are covered with spicules like those of the 

 interior, but smaller, with the addition of spindles, clubs, approximately foliate clubs, 

 and very small irregular bodies. On the surface of the stalk there are minute irregular 

 bodies, capstans, and double-clubs. 



32. Sclerella jpratti, nom. n. (Plate 6. fig. 10 ; Plate 13. fig. 11.) 

 = Paranephthya pratti, Thomson and Henderson. 



Por description see : — 



Thomson and Henderson : Ceylon Pearl Oyster Fisheries Keports, No. xx. 1905, pp. 284-285, 

 pi. 2. fig. 6, pi. 5. fig. 18. 



A number of specimens of this puzzling form afford an opportunity for a better 

 diagnosis of the species, based by Thomson and Henderson on a single small specimen, 

 which they placed under Wright and Studer's genus Farcmephthya. Kiikenthal has 

 since shown (Wissenschaftliche Ergebnisse deutsch. Tiefsee-Expedition, 1898-1899 

 (1906), Bd. xiii.) that the genus Paranephthya must be merged in his emended genus 

 Capnella, and, misled by the inadequacy of the description of Paranephthya pratti, he 

 has not unnaturally sought to make it follow its genus. While admitting tliat Para- 

 nephthya may be merged in Capnella, we cannot agree that this can be done with the 

 forms named P. pratti, for which we now propose a new genus. The stalk portion is 

 densely filled with massive, very irregular spicules lying on the canal- walls, and presents 

 an appearance quite different from that seen in Capnella, where numerous small spicules 

 occur in the same position. The unfortunate use of tlie word " zooids " and " degenerate 

 in character " in the original description of this puzzling form led Kiikenthal to infer 

 that dimorphism w^as indicated, which was not the intention of the authors. 



