82 BULLETIN 151, UNITED STATES NATIONAL MUSEUM 



Apart from coloring, ahli is said to difFor in its larger size; the 

 type, a female, measures 50 mm. The three largest females in the 

 Limibo scries are 46, 46, and 45 mm., respectively; 17 of the 30 

 Lumbo skinks are over 40 mm.; 6 of these are males ranging from 

 40 to 43 mm., with an average of 41.1 mm.; 11 are females ranging 

 from 40 to 46 with an average of 43.3 mm. Whether the type of 

 ahli is abnormally large or of average size on the island it is difficult 

 to say with so small a series as Mertens had at his disposal. 



I have often been struck by the more vivid coloring presented 

 by Mombasa skinks as opposed to those from Pemba, Dar es Salaam, 

 and Lumbo, and in general these Mombasa skinks though lighter 

 than those from further south are darker than Australian peronii. 

 In the nine lots of that race (excluding African) in the Museum of 

 Comparative Zoology, however, at least two skinks are indistinguish- 

 able from Mombasa specimens. These are No. 7672 from British 

 Papua and 9490 from Darnley Island, Torres Straits. 



As already hinted East African houtonii may be divisable into 

 a northern and southern race on the basis of average number of scale 

 rows, darker coloring of the southern specimens, and possibly slightly 

 larger size of the southern specimens. The Mombasa skinks, how- 

 ever, can only be separated from typical peronii on a basis of average 

 color difference. 



Such questions naturally arise as to how far we are justified in 

 accepting racial names based on color variations only; and if done, 

 is not such a course bound to lead to endless confusion? Boulenger 

 says that the races of houtonii are "irregularly distributed over the 

 hotter parts of both hemispheres." How came houtonii to be so widely 

 distributed? The theory that human agency has played no small 

 part seems inescapable. If human agency was responsible for trans- 

 porting these little skinks in times past when there was much less 

 sea-borne traffic than there is to-day, is it not reasonable to suppose 

 that the settlements of these skinks are being augmented at the 

 present time by arrivals from other coasts? 



It is not difficult to theorize as to how such transportation takes 

 place at Lumbo, where I spent six months and observed the methods 

 of loading and unloading barges and dhows, which at that time was 

 taking place daily. At Lumbo there is a low, shelving shore of sand 

 and coral rag, and it is in the fissures and crannies of the latter that 

 the skinks take refuge from the incoming waves. As the waves 

 retire the skinks emerge from their retreats to hunt for shrimps, 

 sea slaters, and other small marine creatures which are stranded in 

 the numerous hollows of these rocks. When a steamer or dhow 

 arrives, of necessity it anchors a long way from the beach, transfers 

 its cargo to boats which are able to approach several hundred yards 

 nearer, once again the cargo is transferred, this time to the heads of 



