408 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 21 



Size and sex: Males are from 15.5 to 66 mm, females from 11.5 to 

 73 mm, and young from 5.6 mm. Crane (1937) records ovigerous fe- 

 males from 69.5 to 81.5 mm. 



Breeding: Gulf of California in April. (Crane) 



Measurements: For convenience in comparison, measurements of the 

 largest male and female examined are given in tabular form: (in milli- 

 meters) 



Remarks: Evidence has been accumulating to support the suggestion 

 of Rathbun (1925, p. 461 ff.) that specimens formerly identified as 

 Stenocionops triangulata are actually the young of S. macdonaldi. In 

 recording 12 females measuring 61.5 to 81.5 mm and a single male 

 measuring 37.5 mm, Crane (1937, p. 62) suggested that a still smaller 

 specimen be secured before the two species were synonymized. Velero III 

 specimens bridge at regular intervals the gap between the 30 mm S. 

 triangulata and the 93 mm S. macdonaldi for which measurements were 

 given by Rathbun {op. cit.). A 73 mm female from Bahia Honda, 

 Panama, has the two principal hepatic spines but lacks the supplementary 

 hepatic spinule of the 88 mm holotype of S. macdonaldi. Its rostrum 

 is equal to one-eighth the carapace length, instead of one-twelfth. A 66 

 mm male from Panama has also two hepatic spines and a rostrum equal 

 to one-eighth of the carapace length. In a 43 mm female from Panama 

 the anterior hepatic spine is but half the size of the posterior or principal 

 hepatic spine, and the rostrum is between one-sixth and one-seventh the 

 length of the carapace. 



