326 ROBERT TRACY JACKSON ON ECHINI. 



I take pleasure in naming this genus in memory of the late Sven Love"n, past master in the 

 study of the structure of Echini, and whose methods of work have been of incalculable service 



to me. 



Key to the Species of Lovcnechinus. 



Four columns of plates in an interambulacral area . . . L. lacazei (Julien), p. 326. 



Five columns of plates in an interambulacral area; occluded and demi-plates meeting in serrated suture 



L. mutatus (Keyes), p. 335. 

 Five columns of plates in an interambulacral area; occluded and demi-plates meeting in interlocking 



tongue-like suture; test massive L. nobilis (Meek and Worthen), p. 335. 



Five, or in part, occasionally, six columns of plates in an interambulacral area; occluded and demi-plates 



meeting in tongue-like suture; test not massive as in nobilis . . . L. missouriensis (Jackson), p. 337. 



Six (or possibly more) columns of plates in an interambulacral area; the plates are very wide and high, 



but not thick; occluded and demi-plates meeting in tongue-like suture . . L. anglicus sp. nov., p. 346. 



Seven columns of plates in an interambulacral area; occluded and demi-plates meeting in serrate suture 



L. septics sp. nov., p. 348. 

 *Lovenechinus lacazei (Julien). 

 Text-figs. 240-243, p. 331; Plate 35, figs. 4-7; Plate 36, figs. 1-8; Plate 38, figs. 1-3. 



1 Palaechinus sphaericus Koninck, 1869, p. 546, Plate [not numbered], fig. 1 ; 1870, p. 259, Plate 7, fig. 1 ; 



Baily, 1874, p. 41; Zittel, 1879, p. 484; Neumayr, 1881, p. 151; A. Agassiz, 1892, p. 73. 

 1 Palaeechinus sphaericus (pars) Loven, 1874, p. 41. 

 1 Eriechinus sphaericus Pomel, 1883, p. 114. 



1 Typhlechinus sphaericus Neumayr, 1889, p. 362, text-fig. 82e. 



2 Palaeechinus ellipticus Duncan, 1889, p. 200, text-fig, viii (non M'Coy, 1844). 



Pdaechinus lacazei Julien, 1890, p. 737; 1896, p. 128, Plate 16, figs. 3-5; Fraipont, 1904, p. 9, Plate 1, fig. 



8; Plate 2, figs. 1-6; Klem, 1904, p. 34. 

 1 Palechinus sphaericus Tornquist, 1897, p. 736. 

 2 Palechinus ellipticus Tornquist, 1897, p. 739. 

 Palechinus lacazei Tornquist, 1897, p. 742, Plate 20, figs. 1-4; Plate 21, fig. 1. 



1 Palaechinus sphericus (pars) Klem, 1904, p. 34. 

 Pdaechinus sp. Fraipont, 1904, p. 9, Plate 2, figs. 7, 8. 



2 Maccoya ellipticus Lambert and Thiery, 1910, p. 119, (this is based on Duncan's, 1889, description and 



figure). 

 Maccoya lacazei Lambert and Thiery, 1910, p. 120. 



1 These references are all in regard to the specimen from Kirkby Stephen (text-figs. 240-243), described by de Koninck 

 as Palaechinus sphaericus. He stated that the oculars are wanting, a mistake which has proved unfortunate as on this 

 character were based the two genera Eriechinus and Typhlechinus. As these two genera were based on an erroneous ob- 

 servation, and their types are not the species supposed, they are considered out of court as generic names (see footnotes 

 pp. 303, 312). The Palaechinus sphaericus M'Coy (1844, p. 172, Plate 24, figs. 5a-5c) is an entirely distinct species and 

 is here considered as Maccoya sphaerica, pp. 317, 318; Plate 32, figs. 4-5; Plate 34, figs. 4-10. 



* These references are all in regard to the specimen from Helsington Barrows in the Jermyn St. Museum, described 

 by Duncan (1889, p. 200, text-fig, viii) as Palaeechinus ellipticus; but here referred to Lovenechinus lacazei (footnote p. 303, 

 p. 328, Plate 36, figs. 1-3). The Palaechinus ellipticus M'Coy (1844, p. 172, Plate 24, figs. 3a-3d) is an entirely distinct 

 species and is here considered on p. 307, Plate 29, fig. 2, Plate 30, figs. 8-10. 



