308 MR. F. F. LAIDLAW ON THE (Apr. 21, 
(c) Prostate not chambered. 
4. L. panamensis v. Plehn. Gulf of Panama [7]. 
5. L. californica v. Plehn. California, Chatham Is. [11] 
6. LZ. nationalis v. Plehn. Ascension Is. [8]. 
The following also belong to section A, but their position in 
the section cannot be determined without information as to the 
prostate characters. 
L. variabilis Giard. | 
L. ellipsoides Vervill. New England [13]. 
L. virilis Verrill. 
L. drebachensis Oersted. | Norway [6]. 
L. fallax (de Quatvefages) [6] should perhaps form a separate 
section of the genus on account of the great_length of its stylet. 
It occurs on the south side of the English Channel. 
B. Penis unarmed. 
a. Prostate chambered. 
7. L. chierche von Plehn. Callao [7]. 
(3. Prostate not chambered. 
8. L. pallida (de Quatrefages). Mediterranean [6]. 
9. sp. (unnamed). Maldives [4]. 
y. No definite prostate. 
10. Z. pacificola von Plehn. Valparaiso [7]. 
ll. LZ. malayana, sp. n. Straits of Malacca. 
Belonging to this section but of uncertain position in it is 
L. angust Vervill [13] from New England. JL. lacteoalba Vervill 
[14] is insufficiently characterised, but said to be like L. pallida. 
SEMONIA PENANGENSIS, Sp. 0. 
Two specimens from Pulau Bidan. No note available as to 
colour. This interesting species agrees fairly closely with the 
only other species of the genus at present known, viz., S. macu- 
lata von Plehn, from Java [7]. It is, however, readily distinguished 
from that species by its external characters, the arrangement of 
the eye-spots being obviously very different and showing some 
approximation to the condition found in Discocelis tigrina (see 
text-fig. 53, p. 309). | 
The dimensions of the larger specimen are as follows :— 
Total length, about ...... 22 mm. 
Bread thwaboutperrssere.cr. INS 
Mouth-opening, about ... 9 ,, from the hind end. 
Genital aperture ......... 1 ,, behind mouth-opening. 
Brainy about mesessceerrreec 4 ,, from the anterior margin. 
The marginal eyes extend back for about 8 mm. on either side. 
The arrangement of the brain and tentacle-eyes is shown in 
text-fig. 53, p. 309. 
An important distinction between this species and Semonia 
maculata is afforded by the fact that in the latter the testes and 
