78 J. H. Koeppern on the 



Family VELELLID^E, Brandt, 1835. 

 Genus Velella, Lamarck, 1816. 

 Velella velella, Linnseus, 1758. 



Tehlla sjiimns (Forskal, 1775). 



In accordance with the strict application of the rules of priority, 

 V. velella seems to be the correct name of this species. Specimens were 

 obtained at Station 51 (1 27' N., 27 56' W., temp. 80-1, Dec. 8th, 1902), 

 and at Station 53 (0 55' N., 29 22' W., temp. 79'8, Dec. 10th, 1902). One 

 well-preserved specimen is unlabelled, but lias possibly been caught at 

 Station 52 (1 22' N., 28 10' W., temp. 80, Dec. 9th, 1902). According to 

 the Zoological Log J Velella; were also seen during the voyage at 



Stat. 61. 3 38' S. 33 20' W. Temp. 79 Dec. 13th, 1902. 



Stat. 95. 32 15' S. 47 30' W. Temp. 74'9 Dec. 27th, 1902. 



Stat. 360. 40 59' S. 55 04' W. Temp. 61-6 Jan. 25th, 1904. 



Stat. 362. 43 33' S. 55 07' W. Temp. 60 C Jan. 27th, 1904. 



If the specimens are regarded from their longer side, the sail or crest runs 

 from N.E. to S.W., as Agassiz found to be invariably the case in hundreds 

 of Velellffi which he observed. Out of seventy-seven specimens examined 

 by Chun, 2 seventy-one were of the type described, but in six the crest ran 

 from S.E. to N.W. Lens and van Riemsdijk B state that in all five specimens 

 of V. pacifica, collected by the Siboga expedition, the direction of the crests 

 was S.E. to N.W. 



The three Velella; from the " Scotia," Station 51, were partly macerated ; 

 they measure respectively 42, 66 and 68 mm. in length, 16, 26 and 36 mm. 

 in breadth, and the crest is 16, 29 and 23 mm. in height. Nine specimens, 

 all of which are macerated, so as to leave only the chitinous 4 supporting 

 substance, were taken at Station 53. The average dimensions of the 

 " Scotia " Velella3 are, approximately, length 54 mm., breadth 20 mm., and 

 height of crest 20 mm. On four of the specimens from St Paul Rocks, 

 numerous white spiral coils, measuring from 2 to 9 mm. in diameter and 

 being of a beady appearance, were observed. A microscopic examination 

 showed them to be segmented eggs, probably those of a gastropod. As 

 regards the distribution of the genus Velella in the Atlantic, the Flannan 



1 Scott. Nat. Antitrr. EJ-JKI!., " Sci. Results Voyage ' Scotia,'" vol. iv., pt. i. (1908). 



2 C. Chun, Die Siphonoplioren der I J lnl /.,//-AVyi. ilitiuii, Kiel and Leip/.ig (1897). 



3 A. D. Lens and T. van Riemsdijk, Tlie tiiphonopliora of the Sibot/a Expedition, 

 Leiden (1908). 



4 M. Henze, "Notiz iiber die chemische Zusammensetzung der. Geriistsubstanz von 

 Velella spirans," Hoppe Seyler's Xs. physiol. Chemie., L.V. (1908). 



(ROY. PHY. soc. FKOC., VOL. xix., 17.) 



