September 12, 1884.] 



SCIENCE, 



223 



Mr. Pourtales' first dredgings, were written under 

 very considerable difficulties, as I well remember 

 hearing from the author himself. But the ' priority 

 in scientific research,' which Mr. Rathbun claims for 

 Pourtales' work, had been accorded to it four years 

 previously, at the earliest pos>ible opportunity, in 

 the Proceedings of the Royal society. So far as I 

 know, this honor has never been ' denied ' to one 

 who would have been the last to claim it for himself. 

 I fully admit, however, that the date of his earlier 

 work has been incorrectly given in certain popular 

 accounts of the subject; but this was done acci- 

 dentally, and without the slightest intention of 

 appropriating any credit for the work of British 

 naturalists which was justly due elsewhere, as will 

 be evident from what I have said already. 



P. Herbert Carpenter, 



Eton college, "Windsor, Eng., 

 Aug. 11. 



The 



bassalian fauna ; ' 

 asteriscus. 



Pentacrinus 



I notice that Mr. Gill has "recently proposed the 

 name 'bassalian realm' for the collective deep-sea 

 faunas." I do not know whether it is proposed to 

 define this name more strictly by assigning to it any 

 particular bathymetrical limits; but it may be well to 

 notice, that, in bis presidential address to the biologi- 

 cal section of the British association at Plymouth in 

 1877, Mr. Gwyn Jeffreys suggested the use of the 

 name "'benthal' (from the Homeric word (Hevdoc, 

 signifying the depths of the sea) for depths of one 

 thousand fathoms and more," while retaining the 

 term ' abys>al ' for depths down to one thousand 

 fathoms. 



There is another point to which I have long thought 

 of directing the attention of the readers of Science, 

 and I therefore take this opportunity of doing so. 



The surveys of Hayden, Wheeler, and others, in 

 Utah. Idaho, and Wyoming, have revealed the very 

 wide distribution, in beds of Jurassic age, of a cri- 

 noid which has been called Pentacrinus asteriscus. 

 Nothing is known of this form but a number of 

 stem-joints (I speak under correction, and shall be 

 pleased to hear that I am wrong); but most of the 

 figures of these joints which I have seen (e.g., that 

 given by White in the paleontology of Wheeler's sur- 

 vey) seem to me to indicate that the type should be 

 referred to Extracrinus rather than to Pentacrinus. 

 The essential characters of the stem-joints of Extra- 

 crinus are well shown in plate liii. of Buckland's 

 'Geology and mineralogy,' figs. 9-13; on tab. 101 of 

 Quenstedt's 'Encriniden,' especially figs. 24, 27, 33, 

 and 37; and also on plate xii. of the Austins' ' Mono- 

 graph of recent and fossil crinoids.' The five in- 

 terradial petals are quite narrow, and much less 

 distinctly oval than in Pentacrinus, sometimes be- 

 coming almost linear, with rounded outer ends. The 

 interpetaloid spaces are plain, and devoid of sculp- 

 ture; while the markings at the sides of the petals 

 are much more delicate than in Pentacrinus, having 

 more the character of striae or crenulation than of 

 coarse ridges. They are also much more numerous 

 than in Pentacrinus, and are limited to the sides of 

 the petals, not reaching the outer edge of the joint- 

 face. Under these circumstances, I suspect that it 

 is to Extracrinus, and not to Pentacrinus, that we 

 must refer the joints which were described by Meek 

 and Jlayden as having lance, oval, petaloid areas, 

 "bounded by rather narrow, slightly elevated, trans- 

 versely crenulate margins." 



Extracrinus was proposed by the Austins for the 

 two well-known liassic fossils, Pentacrinus briareus 



and P. subangularis; but recent investigations have 

 shown that the genus extends up into the great 

 oolite (Bathonien) of Britain, France, and Switzer- 

 land. I have no knowledge, however, of any triassic 

 species of Extracrinus; though Pentacrinus is well 

 represented in the St. Cassian beds, and has been 

 found associated with Encrinus in the 'wellenkalk' 

 of Wiirtemberg. 



It is therefore interesting to find that the triassic 

 form of Pentacrinus asteriscus, which was obtained 

 by the fortieth parallel survey from the Dun Glen 

 limestone and the Pah Ute range, differs from the 

 Jurassic specimens found in south-east Idaho and 

 western Wyoming, almost precisely in those points 

 which distinguish Pentacrinus from Extracrinus. 

 According to Hall and Whitfield, the chief distinc- 

 tion of the triassic forms lies "in the more obtuse 

 points of the star, and the filling-up of the angles 

 between the points, and also in the broader form of 

 the elliptical figures on the articulating surfaces of the 

 disks." They suggest that the differences may pos- 

 sibly be of specific value; but, having carefully 

 studied a large variety of stem-joints of Penta- 

 crinidae, both recent and fossil, I am inclined to go 

 farther, and to suspect. that the triassic type may be- 

 long to Pentacrinus, but the Jurassic form to Extra- 

 crinus. 



The two genera differ very considerably in the char- 

 acters of the calyx and arms, as will be fully ex- 

 plained in the report on the Pentacrinidae dredged 

 by the Challenger and the Blake, which will appear 

 in the course of the winter. But, in the mean time, I 

 shall be most grateful for any information respecting 

 Pentacrinus asteriscus, in addition to that which has 

 been already made public; and I need not say that I 

 should much like to have the opportunity of making 

 a personal examination, both of the triassic and the 

 Jurassic specimens. P. Herbert Carpenter. 



Eton college, Windsor, Eng., 

 Aug. 11. 



Points on lightning-rods. 



The following passage occurs in J. E. H. Gordon's 

 excellent "Physical treatise on electricity and mag- 

 netism," vol. i. p. 24: "It was held that the knobs 

 [on the ends of iightning-rodsj must be most effica- 

 cious, because the lightning was seen to strike them, 

 and never struck the points. The fact that a point 

 prevents the lightning from ever striking at all was 

 not known." 



This is not true. The highest rod on my house is 

 some fifteen feet above the others, and about thirty 

 feet higher than the surrounding buildings; and yet, 

 notwithstanding the fact that it is tipped with a 

 brush of five points, it was struck a few years ago. 

 The points are gilded iron, and the topmost one was 

 melted into a ball about one-eighth of an inch in 

 diameter. The rods are all connected by horizontal 

 pieces held about three inches from the tin roof by 

 glass insulators, after the fashion of ignorant light- 

 ning-rod agents. The neighbors say that the sparks 

 flew so thickly between the rods and the roof, as to 

 resemble a sheet of flame. The shock was, singularly 

 enough, so slight that it is doubtful whether it was 

 due to the electrical discharge, or the deafening crash 

 of thunder that instantly followed the splitting sound 

 of the spark. A. B. Porter. 



Indianapolis, Aug. 23. 



Photographs of the interior of a coal-mine. 



One of the most interesting enterprises to which 

 the preparations for the New Orleans exposition have 



