200 
with massive warty spindles. But according to Kolliker (1865) there is a single layer in 
Acis guadahipensis Duch. and Mich., and two layers in Thesea, the inner one with 
smaller spindles. 
(2) For forms which had been referred by Nutting to the genus Thesea, Kukenthal established 
the new genus Pseudothesea, which is marked by unilateral, high-thorned, plate-like, modified 
spindles, plus various other forms like clubs and thorns. 
(3) But this unilateral development was emphasised in Kolliker’s definition of Thesea, with 
special reference to T. exserta , which Kukenthal identified with T. guadahipensis and used 
in his Gorgonaria (1924) as the type of a re-instated genus Thesea, from which Pseudo¬ 
thesea is separated oft because of its unilateral spindles ! Thus he used as the distinctive 
feature of a new genus Pseudothesea, what was originally regarded as characteristic of Thesea. 
It seems to us, therefore, that Pseudothesea is not a well-defined genus and that Nutting’s 
species (Siboga XIII b) should retain the old name Thesea. 
Genus Thesea. 
1. Thesea placoderma Nutting. 
For description see: NUTTING, Muriceidae of the Siboga Exp. XIII b, 1910, p. 54, 3 figs. 
Stat. unrecorded. 1 Ex. 
A fragment of a brownish colour, 2.9 cm. in length, with a maximum diameter of 3 mm. 
The verrucae are practically contiguous. The points gf the crown and points consist of two 
heavy spicules sloping towards each other. The colourless spicules show (1) numerous unsym- 
metrical forms of the characteristic Thesea type with very large teeth on one side, (2) numerous 
rough stars with branched processes on all sides, (3) forms that approach the Acamptogorgia 
type with divaricate base and a projecting foliaceous spine which tends to be compound. 
Previously recorded by Nutting from Siboga Station 310. 
2. Thesea sanguinea Nutting. 
For description see: NUTTING, Muriceidse of the Siboga Exp. Xlllb. 1910, p. 55, 3 figs. 
Stat. 240. Banda. 9— 36 M. 1 Ex. 
A fragment of a red colour, 2 cm. in length and 1.5 mm. in thickness, without any 
branching left. The ccenenchyma is covered with large very warty spindles, some with markedly 
unilateral prongs. There are other shapes — such as crosses and approximate stars. The low 
calyces have their margin surrounded by a circlet of blunt but prominent knobs. 
Previously recorded by Nutting from Haingsisi, Siau Island, Aru Islands, and Sailus 
Besar, Paternoster Islands. 
Genus Acis. 
1. Acis sqziamata Nutting. (Plate V, Fig. 2; Plate XVI, Fig. 9). 
For description see: NUTTING, Muriceidae of the Siboga Exp. XIII b, 1910, p. 42, 3 figs. 
Stat. 105. 6° 8' N., 121 0 19'E. 275 M. Coral bottom. 1 Ex. 
Stat. 251. 5°28'.4S., I32 °o'. 2E. 204 M. Hard coral sand. 1 Ex. 
