354 SIR SIDNEY F. HARMER ON 
large development of cryptosyst proximally. Bifurcation of types 9-12 
(fio's. 9-12), the joints traversing the proximal ends of the zooecia CG and 
DF ; one or other of the joints occasionally suppressed. F and G usually 
separated on the basal side of E, sometimes by its whole width, their 
proximal segments shorter than the corresponding parts of C and D. The 
proximal ends of F and G may be suppressed, in which case the internode 
consists of a single zocecium at its proximal end, and the joint consists of a 
single chitinous tube. Rootlet given off on the proximal side of the joint. 
Scutum, marginal and frontal avicularia present or wanting. Basal avicu- 
laria and vibracula wanting, but probably represented by the rootlet pore- 
chamber. 
Among the species which I include in Tricellaria are the following : — 
A. Internodes biserial at the proximal end. Joints composed of two 
chitinous tubes (figs. 9-11). 
1. Tricellaria ternata {EU. Sf Sol.]. (Fig. 9.) 
Cellaria ternata, Ellis & Solander, 1786, p. 30. Aberdeen. 
Menipea ternata, Hincks, 1880, p. 38, pi. 6. figs. 1-4. British coasts. 
This common species has often been described. I may draw attention to 
the possibility, mentioned on p. 324, that the structure from which a rootlet 
may arise in this species may represent a basal heterozocecium — a structure 
•otherwise absent in the genus. 
la. Tricellaria ternata {Ell. Sf Sol.), var. gracilis, Smitt. 
Cellularia ternata, ioxraa, gracilis, Smitt, 1868, Ofv. K. Vet.-Akad. Ftirli. xxiv. (1867), 
pp. 282, 305, pi. 16. figs. 10-16. Spitsberg;en to Britain and Belgium. 
Menipea gracilis. Busk, 1878, in Nares, Narr. Voy. Polar Sea 'Alert' and 'Discovery,' 
ed. by H. W. Feilden, ii. p. 284. 
It may be observed that gracilis as the trivial name of this form is ante- 
'dated by Cellarina gracilis, Van Beneden, 1848 (see Sect. II.) . 
2. Tricellaria occidentalis (2Va«/:), 1873 *. (Fig. 10.) 
Menipea occidentalis, Trask, 1873, Proc. Calif. Acad. Nat. Sci. i. (1854-1857), 2 ed. 
p. 113, pi. 4. fig. 4. 
„ „ Robertson, 1905, Univ. Calif. Publ, Zool. ii. p. 2,54, pi. 6. figs. 
22-25. California. 
„ cimpacta, Hincks, 1882, A. M. N. H. (5) x. p. 461. Queen Charlotte Is. 
3. Tricellaria pribilofi (Robertson). 
Menipea pribilofi, Robertson, 1905, t. cit. p. 257, pi. 7. figs. 32, 33; pi. 8. fig. 34. 
Alaska, islands of Bering Sea. 
* The Proceedings of the California Aeademy for 1854-1857 were originally printed in a 
newspaper, ''The Pacific," but were republished, verbatim, in 1873. Dr. Trask's paper was 
read at the meeting, Mar. 30, 1857. 
