NO. 2 DEICHMANN : HOLOTHURIOIDEA ; PART II, ASPIDOCHIROTA 319 



on the material examined by Theel and some received from the Arc- 

 turus, but she also included and figured some material of a new species 

 which later, in 1954, was described by Caso (see below). The variety is 

 herewith given full specific rank, and the accompanying figures of 

 Selenkothuria erinaceus (PI. 7, figs. 10-15) will justify the suppression 

 of Holothuria marenzelleri. 



The species has its closest affinities with Selenkothuria erinaceus 

 (Semper), which is known with certainty from as far eastward as Fiji 

 (Theel's material in Stockholm and material examined by me in the 

 British Museum). But judging by the available material, the latter 

 species does not reach the colossal size of S. theeli. 



The Hancock material of Selenkothuria theeli ranges from 1 to 12 

 cm in length, but the larger individuals are often so strongly contracted 

 that one could expect them to reach a length of 20 cm when fully ex- 

 panded. 



The time of the year during which the Hancock material was col- 

 lected, the winter and early spring, may explain why the gonads all 

 appear small. From Bindloe Island, in the Galapagos, a series of 9 well 

 expanded specimens were collected, ranging in length from 1 to 8 cm. 

 The smallest (1 cm in length) individual, which I would estimate to be 

 about six to nine months old, lacks gonads completely, as does also the 

 next stage, which is 2 or 3 cm long and probably a year older. In the 

 individuals 6 or 7 cm long, the gonads measure 0.5 cm in length, while 

 in the largest individual, 8 cm long, they measure 1 cm. Possibly this 

 stage, which probably is about five years old, or the following stage, 

 will develop ripe gonads during the summer months, but this is of course 

 merely speculation. 



Selenkothuria portovallartensis (Caso) 

 PI. 6, figs. 18-21 



Holothuria portovallartensis Caso, 1954, p. 423, pis. 4-10, 224 figs. 

 Holothuria marenzelleri Ludwig, var. theeli Deichmann (partim), 1938, 

 p. 370, fig. 6. 



Diagnosis: Resembling Selenkothuria theeli Deichmann, with 12- 

 20 tentacles, bushy and in younger individuals often of different size. 

 Stone canal usually single, with elongate head, usually one Polian vesicle 

 and small Cuvierian organs. 



Spicules flattened rods or bars, often slightly curved, with few to 

 many holes in the ends and with increasing age developing a lacelike 

 festoon of holes along the edges. A low ridge often present along the 



