440 On the Jcrhoa of Mnscnt. 



Account of other Species." TJosnltats dea Explorations entre- 

 prises aux Indes N(5erlaudaises Orientales en 1899-]900 a bord dii 

 ' Sibo<ra,' livr. xxii. monogr. 2G bis, Leiden, 1905, pp. l;i2, 14 plates 

 and 2 text-fifjures. 



(7) IIarmeu, S. F., and Rideavood, W. G. "The Pterobranchia of 



the Scottish National Antarctic Expedition, 1902-1904." Trans. 

 Roy. Soc. Edinb. xlix. 3, 7, 1913, pp. 531-505, 2 plates and 5 text- 

 figures. 



(8) Lankkster, E. R. Article '' Polyzoa," Encycl. Britann. od. 9, xix, 



1885, pp. 429-441. (Contains the first published fi-ures of 

 Cephalodiscus, made from drawings supplied by Prof. M'lntosh.) 



(9) . "On a new Species of Cephalodiscus (C. niyi-esceiis) from 



the Antarctic Ocean." Proc. Roy. Soc. London, 1905, Ixxvi. B, 

 pp. 400-402, 1 plate. 



(10) M'Intosh, W. C. "Preliminary Notice of Cephalodiscus, a new 



Type allied to Prof. Allman's Uhabdopleura, dredged in II. M.S. 

 ' Challenger.' "' Ann. & Mag. Nat. Hist. (5) x. 1882, pp. .387-348. 



(11) . " Preliminary Note on Cejyhalodiscus, a neyf Form allied to 



Prof. Allman's Jihahdoplcura.'" Rep. Brit. Assoc. (Southampton, 

 1882) 18S3, pp. 506-597. 



(12) . "Report on Cephalodiscus dodecalophus." 'Challenger' 



Reports, Zool. xx. 62, 1887, with an Appendix by S. F. Ilarmer, 

 pp. 48, 7 plates and 6 text-figures. 



(13) RiDEWOOD, W. G. " A new Species of Cephalodiscus (C. gilchristi) 



from the Cape Seas." Marine Investigations, South Africa, iv. 

 (Cape Town, 1906) pp. 173-192, 3 plates and 5 text-figures, 

 (i:).) . "Pterobranchia; Cephalodiscus." National Antarctic Expe- 

 dition [' Discovery '], Nat. Hist. ii. (Loudon, Brit. Mus.), 1907, 

 pp. 1-67, 7 plates and 17 text-figures. 



(15) . " On Specimens of Cephalodiscus niyrescens supposed to have 



been dredged iu 1841 or 1842." Ann. & Mag. Nat. Hist. (8) x. 

 1912, pp. 550-555, 1 text-figure. 



(16) . British Antarctic ('Terra Nova') Expedition, 1910; Nat. 



Hist. Reports, Zool. iv. 2, Cephalodiscus (London, Brit. Mus.), 1918, 

 pp. 11-82, 5 plates and a map, and 12 text-figures. 



(17) . Australasian Antarctic Expedition, 19li-1914, Sci. Reports, 



ser. C, iii. 2, " The Pterobranchia," 1918 (Sydney), pp. 25, 2 plates 

 and 3 text-figures. 



(18) . "A Key for the Ready Identification of the Species of 



Cephalodiscus:' Ann. & Mag.' Nat. Hist. (9) v. 1920, pp. 407-410. 



(19) ScHEPOTiKFF, A, "Die Pterobranchier des Indischen Ozeans." 



Zool. Jahrb., Abth. Syst. xxviii. 4, 1909, pp. 420-448, 2 plates. 



EXPLANATION OF PLATE XII. 



Photographs, of the natural size, of two specimens of Cephalodiscus densus, 

 Andersson, di'edged by the ' Challenger ' in Royal Sound, Ker- 

 guelen Island, Jan. 17th, 1874, from a depth of 25 fath. A, top 

 view ; B, side view. 



XLIII. — The Jerboa of Muscat. By Oldfield Thomas. 



(Published by permission of the Trustees of the Britisli Museum.) 

 While determining an example of Jaculus loftiisi obtained 

 near Baghdad by Major Ciiee.snian, my attention has been 

 drawn to the examples from Muscat presented by Dr. Jayakar 

 and hitherto referred to the same species. But with six 



