590 Frederick Chapman : 



Description of Fossils. 



[The following diagnoses of the specific forms are based on the 

 material to hand, though these may require some further emenda- 

 tion as to specific boundaries and relationships.] 



Order CALYPTOBLASTEA. Fam. Lafoeidae. 



Genus Archaeolafoea, gen. nov. 



Generic Characters. — Hydrocaulus slender, fiexuous and with few 

 lateral branches. Length about 40 mm. Hydrothecae long-coni- 

 •cal, narrowing slightly towards the base; aperture circular; 

 borne equally along the sides of the axis and the branches, and 

 .set at angles of 15° to 50°. Periderm transversely wrinkled. 

 Oonotheca small, elongately pyriform. 



Ihis generic type resembles the living genus Lafo'ea, Lamouroux,^ 

 -which is a common form in European and North American waters, 

 and also occurring in the West Indies and the Straits of Magellan. 

 The living specimens of the genus have not yet provided any 

 examples with gonosomes. 



Archaeolafoea longicornis^ gen. et sp. nov. (Plate XIX., Fig. 1. la; 



Plate XX., Fig. 5). 



Description. — Axis of hydrocaulus slender, fiexuous. Occasion- 

 ally with secondary branches. Hydrothecae long, gradually taper- 

 ing near base- and often geniculate. Aperture circular and slightly 

 everted. Periderm of thecae marked with, fine transverse wrinkles. 

 Axis scaly. Gonothecae, long-pyriform, shorter than hydrothecae. 



Length of hydrosome about 40 mm. Width of axis, .5 mm. 

 Length of hydrothecae about 5 mm. Length of gonothecae about 

 "2 mm. 



Observations. — x^s regards the general form and disposition of 

 the hydrothecae the above species reminds one of Lafo'ea fruticosa, 

 Sars.2 The axis in th€J fossil form is, however, flexible and twisted 

 and does not show the vertical ridging and grooves of the living 



1 Expos. Method., 1821. 



2 Beinaerk, over fire Dorske Hydroider, Vidensk. Forhandl., 1862. Hincks, Brit. Hydroid 

 Zooph., p. 202, pi. xli., fig. 2. Ailmaii, Rep. Chall. Zool., vol. xxiii., pt. l.\x., 1888, p. 34, pi. xvi., 

 fig. 2, 2a. 



