DELPHINULA. 



Plate I. 



Genus Delphinula, Lamarck. 



Testa turbinata, subdiscoidea, anfractibus laxiu&cule con- 

 volutis, tuberculis vel spinis retusis plerumque orna- 

 tis, umbilicum plus minusve amplum formantibus ; 

 aperturd rotunda, Integra, margine continue, reflexo, 

 scepe fimbriate . Operculum corneum, spirale. 



Shell turbinated, nearly discoid, whorls rather loosely 

 convoluted, generally ornamented with blunt spines 

 and tubercles, forming an umbilicus of variable di- 

 mension ; aperture round, entire ; margin continu- 

 ous, reflected, often frilled. Operculum horny and 

 spiral. 



The Delphinula, among marine shells, may be regarded 

 as the analogues of the Cyclostomata among land shells, 

 having a round entire aperture without any indication 

 of a columella. Linnaeus referred them to his genus 

 Turbo, Chemnitz distinguished them by the common 

 appellation of Delphinus, and Lamarck associated them 

 together in a genus, in accordance with the existing 

 form of nomenclature, under the title of Delphinula. 



Species 1. (Fig. a & *, Mus. Cuming.) 

 Delphinula impebialis. Delph. testa subdiscoidea, 

 spiniferd et squameo-liratd ; anfractibus olivaceo- 

 viridibus, ultimo pallid'e purpureo, laxe eonvolutis, 

 umbilicum amplum formantibus ; subangulatis, angulo 

 spinis graci/limis, squamaformibus, nigris, superne 

 infiewis, coronate; anfractuum parte alterd spinis bre- 

 vioribus, contrarie infiexis, in seriebus dispositis, in- 

 terstitiis squamis nigris, minutis, sigillatim impositis, 

 ornatd ; spird depresso-concavd. 

 The imperial Delphinula. Shell somewhat discoid, 

 ornamented with spines and ridges of scales ; whorls 

 olive-green, last whorl pale purple, loosely convo- 

 luted, forming a large umbilicus ; rather angular, 

 angle surmounted with a row of black, tall, slender, 

 scale-like spines, bending inwards at the top ; re- 

 maining portion of the whorls adorned with rows 

 of shorter spines bending the contrary way, with 

 rows of minute scales placed one after the other in 

 the interstices ; spire depressly concave. 

 Reeve, Pro. Zool. Soc, 1S42. 



Delphinula melanacantha, Conch. Syst., vol. ii. 

 pi. 211.1". 4. and pi. 212. f. 10. 



Hub. Island of Mindanao, Philippines (found in clefts of 

 rocks and under stones at low water) ; Cuming. 



It requires no very " scrupuleuse observations" to 

 distinguish this shell from either of the species to which 

 it has been at different times referred by M. Kiener ; 

 namely, the D. distorta and laciniata. With the former 

 of these species it is unnecessary to institute a compari- 

 son ; in comparing it with the latter, it may be well to 

 point attention to the manifest difference between the 

 spiny scale-like protuberances of the D. imperialis, and 

 the blunt laciniated appendages of the D. laciniata. 



After publishing this species in my ' Conchologia 

 Systematica' with the specific title of melanacantha, I 

 was reminded that it had been circulated amongst col- 

 lectors with that of imperialis. Though the latter name 

 had appeared only in manuscript, I thought it prudent 

 to adopt it. 



Species 2. (Mus. Cuming.) 

 Delphinula Formosa. Delph. testa rotunda, subdis- 

 coided, leviter nodiferd, aureo-ochraced, cocceo-tinctd, 

 anfractibus perangulatis, angulo squamis grandibus, 

 triangularibus.valde compressis, coronato; anfractuum 

 parte inferiori squamarum minorum seriebus dvahn.-, 

 squamulisque ochraceo-coccineis minutis, in seriebus 

 paralle/is, subflexuosis , dispositis, ornatd ; umbilico 

 amplo, purpureo-lacvo vividi colorato : spied piano- 

 convexd. 

 The beautiful Delphinula. Shell round, nearly dis- 

 coid, slightly knobbed, golden yellow, stained with 

 pinky crimson ; whorls sharply angular, angle co- 

 ronated with a row of large, very compressed scales ; 

 lower portion of the whorls ornamented with two 

 rows of smaller scales and numerous minute yel- 

 lowish crimson scales, arranged in waved parallel 

 rows ; umbilicus large, vividly coloured with bright 

 purple lake ; spire flatly convex. 



Variety ft. 



(Vide Plate III.) 



Reeve, Pro. Zool. Soc, 1S42; Conch. Syst., vol. ii. 



pi. 212. f. 9. 

 Hab. Island of Capul, Philippines (found under stones 

 on the reefs at low water) ; Cuming. 

 The lower portion of the whorls of this beautiful shell 



June 1813. 



