PETTA PUSILLA. 59 1 



formed of coarse but generally regular grains of sand neatly cemented; occasionally 

 smoothly rounded and larger grains are used, or even entire shells (e. g. Rissoa), as well as< 

 fragments of others and stones. 



Synonyms. 

 1865. Petta pusilla, Malmgren. Nord. Hafs.-Annul., p. 361, Tab. xviii, fig. 43. 

 1867. „ „ idem. Annul. Polych., p. 104. 



1871- „ „ Grube. Schles. Gesell. (1870), p. 75, sep. abclr., pp. 4 and 8. 



1874. „ „ Malm. Groteborg. Fauna, p. 94. 



1878. „ „ Storm. Kong. Norske Vid.-selsk. Skrifter, p. 243. 



1879. Pectinaria pusilla, Tauber. Annul. Danica, p. 127. 

 1885. Petta pusilla, Cams. Fauna Medit., vol. i, p. 261. 



1893. „ „ Lo Bianco. Atti E. Accad. Sc. Napoli, vol. v, No. 11, p. 48. 



1894. Pectinaria pusilla, Bidenkap. Christ. Vet.-Akad. Forhandl., p. 120. 



1896. „ „ Appellor. Berg. Mus. Aarb., p. 12. 



1897. „ •'•'•„..' Michaelsen. Polych. deutsch. Meere., p. 160. 

 1900. „ „ Cemmill. Fauna of Clyde, p. 359. 



1909. Petta pusilla, Fauvel. Bull. Inst. Ocean., cxlii, p. 21. 

 1911-12. „ „ Nilsson. Zool. Bidrag Uppsala, Bd. i, pp. 138—9. 

 1912. „ „ Crawshay. Journ. M. B. A., vol. ix, p. 346. 



,, Pectinaria pusilla, Wollebcek. Skrift. Vid.-selsk. Krist., No. 18, p. 35, pi. hi, figs. 1 — 8. 



1914. Petta pusilla, Mcintosh. Ann. Nat. Hist., ser. 8, vol. xiii, p. 94. 



„ „ „ Fauvel. Campag. Scient. Monaco, Fasc. xlvi, p. 279, pi. xxv, figs. 22, 26. 



1915. „ „ Allen. Journ. M. B. A., vol. x, p. 637. 

 1917. „ „ Hessle. Zool. Bidr. Uppsala, No. 5, p. 83. 



Habitat. — Dredged in the " Porcupine" Expedition of 1869 off Ireland in 422 fathoms ; 

 dredged in 567 fathoms in the Atlantic "Porcupine" Expedition, 1870; S.W. Ireland, off 

 Co. Kerry, and in the same region at 52^ fathoms during the Royal Irish Academy's 

 Expedition of 1886 ; Firth of Clyde (Dr. David Robertson) ; Plymouth (Crawshay) ; Irish 

 Sea (Arnold Watson). 



It extends to Sweden (S. Loven, Malm, Hessle) and Northern Seas; Mediterranean 

 (Marseilles, Marion) ; Fayal, Azores and the Atlantic (Fauvel). 



The crown has eleven paleolse on each side, with a pale base which is expanded at 

 the end, the shaft being flattened, little dilated, and then tapered to a blunt (rounded) 

 point. In developing paleola3 a translucent process passes from the blunt tip. The blunt 

 points of these and the coarser nature of the tube as compared with Lagis Koreni are 

 interesting. The five outer paleolas are larger than the others (Lo Bianco). The upper 

 area slopes obliquely backward, and has a smooth edge without a rim. It extends to the 

 ventral edge of the paleolas, where it ends at the anterior cirrus, a smooth area occurring 

 below the paleolae — that is, between them and the veil. This process is clearly a develop- 

 ment of the flattened area of the crown and is independent of the veil. The veil has a 

 high arch and a smooth border, but in two examples the highest point of the arch had 

 three papillse close to each other, the rest of the margin being quite smooth. The veil is 

 of moderate breadth, is attached to the roof of the oral region and gives origin to the 

 tentacles, which form the usual lateral groups and have the typical structure. 



